34 THE CELL ME^IBRANE OF EUMYCETES. 



by Wisselingh in the fungus of the lichen known as Usnea 

 barbafa, and in Geaster furnicatus (a fungus allied to the well- 

 known Bovistes), on which account he named them usnein or 

 geasterin. On the other hand, the substance which Mangix (I.) 

 classed as cellulose in the case of Mucorhiece, Urediime, and 

 Ustilarjinece, does not— according to his own reports— give the 

 typical reactions, and hence cannot lay any claim to recognition. 

 It being thus certain that true cellulose has, so far, been 

 , found in only two families of fungi, it now remains to ascertain 

 the composition of the cell membrane of the others. Thanks 

 to the zeal of several workers, whom we shall mention shortly, 

 satisfactory, and perhaps even surprising, information can already 

 be given on this point ; for it will undoubtedly seem strange to 

 hear that one of the components in question is nitrogenous. 

 This is positively known, and the substance in question will be 

 dealt with in the following paragraphs as being most worthy 

 our attention. Before dealing with this, however, it is advis- 

 able to state, in order to prevent misunderstanding, that the 

 workers in question mostly employ the term fungus-cellulose in 

 the sense of fungus membrane substance. 



§ 226.— Chitin. 



That the residual substance of the cell membrane, after 

 passing tlu-ough various methods of extraction, always contained 

 nitrogen, was recognised not only by investigators — such as 

 ScHLOSSBERGER and DcEPPiNG (I.) — in an age of imperfect analy- 

 tical knowledge, but also more recently by W. Hofmeister (I.) 

 and E. Wixtersteix (I.). The last-named found nitrogen 

 (3.3 to 3.9 per cent.) in preparations from the cell walls of the 

 edible boletus {Boletus edulis) : 3.6 per cent, in the case of the 

 mushroom (Agaricus camjiestris) ; 3 per cent, in the toadstool 

 {Cantharellus ciharms) ; 2.5 per cent, in the common morel (Mor- 

 cliella escubmta) ; 3.3 per cent, in Pejiicilliura (jlaucum, mid 3.9 

 per cent, in a species of Botrytis. Unlike his predecessors, 

 however, Winterstein did not rest content with the comforting 

 belief that the extraction of the nitrogenous matter in the 

 cell membrane had not been effected completely, but convinced 

 himself that nitrogen was also present in such preparations as 

 had been perfectly freed from nviclein and albumin by the pre- 

 vious treatment with caustic potash and Schulze's reagent. It 

 therefore followed that the preparations in question must be partly 

 or entirely composed of some nitrogenous substance. The same 

 discovery, in the main, was obtained independently a few months 

 later by EuG. Gilsox (II.) in his researches on Agaricus campestris 

 and ergot of rye {Secale cornutuni). By fusing the cell prepara- 

 tions therefrom with caustic potash at 180° C, according to the 

 Hoppe-Seyler method, he obtained a residue, not of cellulose but of 



